Hello everyone, I keep getting punctures on my mountain bikes, and the cranks fall off, but that's for later. Before you scoff just bear with me, I have had an idea, would putting a cut up inner tube or even another old tyre between the tube and the tyre work, has anyone done this? It might save me on patches as I have many of both lying around the place, tubes and tyres that is. Also can anyone suggest some cranks that can handle abuse? I have ruined three sets, now on my DiamondBack, I have the good original right hand crank and a good left crank, this one came off a bike with a bockety right crank, this left one is about 1.5cm shorter than the right one , this is why I need three sets of cranks. I don't want to talk about my Raleigh, the wound is too fresh. Thanks in advance.

Last edited by Fladdem on Wed May 16, 2012 10:19 pm, edited 1 time in total.

I keep getting thorns and the odd bit of glass, I try to avoid them. Not tears in the tube but little holes, and that's annoying, it's not that frequent that I am repairing every week but maybe every month.

Using a strip of innertube to line the tyre might help to prevent punctures, but you need to ask youself why you keep getting punctures?

Is it a particular trail you ride on where you keep getting punctures? is it rocky? do sharp bits of flint stick into the tyre and cause the punctures? or are your tyres under-inflated and so the innertube gets squished against the rim causing "snakebite" punctures? Maybe it's a path next to a hedgerow that's recently been cut and there's bits of thorny hedge laying about just waiting to cause a puncture? perhaps you have a rougue spoke which is sticking through the rim-tape on the inside and causing your puctures? do you have rim-tape on your wheels? maybe your tyres are geting worn out and are more prone to being punctured? do you check the inside of the tyre for any foreign objects after repairing a puncture to ensure any thorns etc are removed and can't cause you another puncture?
there's many reasons for punctures maybe you should invest in some tyres which have punture a resistant belt built into their design?

Cranks, are they the square-taper type? do they fit onto a square shape axle with one bolt? usually they fall off because they've not been tightened on properly, but if the square hole in the crank arm is a bit worn or rounded-off then it makes them more likely to come loose and round off a bit more before they fall off again. The soft alloy of the crank arms is easily damaged by the harder steel of the bottom bracket axle if they are allowed to work themselves loose.

If the puncture problem is mostly caused by thorns I recommend using fatter inner tubes. The logic is that if you use an inner tube that is the same size as the tyre then any hole will be the same size as the thorn that made it. So little air can escape as long as the thorn remains in place.

It's similar principle as the magic trick where you stick a piece of sellotape onto a balloon so that you can stick a pin into it without the balloon bursting or going down.

You will also need to inject some puncture sealant into the tube in case the thorns pull out.

This method is not about puncture prevention but stopping the tyre from deflating when it is punctured. This approach can lead to slow punctures caused by a thorn moving as the tyre rolls along. Such a thorn can be easily found because it will bleed puncture sealant. Simply remove the thorn, rotate the tyre so that the hole is at the bottom and then pump it up so as to force puncture sealant into the hole.

If you ever remove the inner tube you must remove the thorns from the tyre before you put it back. I have had 14 thorn holes in one tube without it deflating.

I use Schwalbe AV13F inner tubes that are sized 26"x 2.1"to 3" and weigh only 185g. Motorbike or sit on mower puncture sealant as its cheaper and one bottle will treat several bikes.

You can also use thicker downhill tubes or even downhill tyres. Both are more puncture resistant but weigh a lot more.
Schwalbe AF13D tubes weigh 265g.

Last edited by GrahamJohnWallace on Wed May 16, 2012 11:13 pm, edited 1 time in total.

An old touring trick is to take an old (road) tyre, and cut it back to just the tread portion, then fit this between the tube and tread.
There is (was?) also a product called tuffy tape which did the same thing.

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